The ability of an internal combustion engine to perform in a desired manner may at times depend on its ability to meet certain torque demands. It is known that the torque output of a representative internal combustion engine is speed-dependent over the range of speeds that the engine can develop. A general way to characterize performance of a particular engine model is by graph plots of torque vs. speed and horsepower vs. speed.
While a particular engine model may be representatively described by representative graph plots like those just mentioned, the mass-production usage of such an engine model will yield a universe of actual engines for any one of which actual graph plots like those just mentioned may depart from the representative ones. It is believed that engine and vehicle performance can be improved by utilizing data signals from the actual engine and vehicle to develop an engine net output torque data signal representing the input torque to the vehicle's drivetrain for propelling the vehicle.
The invention endows an electronic engine control system with an ability to develop a data signal that accurately represents engine net output torque produced by a running engine. It is believed that such a signal can be used to improve engine and vehicle performance. For example, an engine net output torque data signal may be used to provide better definition for transmission shift points, particularly automatic transmission shift points. Such a signal may also be a useful input to a vehicle traction control system. It may also serve as a useful diagnostic or maintenance tool.
The present invention relates to an electronic control system for an engine in which the electronic system develops an accurate engine net output torque data signal, based on the actual engine itself, recognizing, and taking into account, a number of various factors that may be different from engine to engine in mass-produced engines. It is believed that at least some of these factors may heretofore not have been perceived as significant in enabling engine and vehicle improvements to be attained.
One general aspect of the invention relates to an electronic control for a combustion engine that forms a portion of an automotive vehicle powertrain and has an output shaft for powering a drivetrain portion of the powertrain to propel the vehicle, the control comprising: at least one ambient parameter variable input source representing a respective ambient parameter useful in deriving gross torque output of the combustion engine; at least one operating variable input source representing a respective operating parameter useful in deriving a reduction in gross torque output of the combustion engine due to operation of the combustion engine; and a processor for processing a respective signal correlated to the at least one ambient parameter variable input source and for processing a respective signal correlated to the at least one operating parameter variable input source to derive torque at the output shaft of the engine for powering the drivetrain to propel the vehicle.
Another general aspect relates to an automotive vehicle comprising: a powertrain that includes a combustion engine having an output shaft powering a drivetrain to propel the vehicle; at least one ambient parameter variable input source representing a respective ambient parameter useful in deriving gross torque output of the combustion engine; at least one operating variable input source representing a respective operating parameter useful in deriving a reduction in gross torque output of the combustion engine due to operation of the combustion engine; a processor for processing a respective signal correlated to the at least one ambient parameter variable input source and for processing a respective signal correlated to the at least one operating parameter variable input source to derive torque at the output shaft of the engine for powering the drivetrain to propel the vehicle; and a utilization device in the drivetrain whose operation is controlled at least at times by the derived torque.
Still another general aspect relates to a method in a control for a combustion engine that forms a portion of an automotive vehicle powertrain and has an output shaft for powering a drivetrain portion of the powertrain to propel the vehicle, the method comprising: measuring at least one ambient parameter variable input representing a respective ambient parameter useful in deriving gross torque output of the combustion engine; measuring at least one operating variable input source representing a respective operating parameter useful in deriving a reduction in gross torque output of the combustion engine due to operation of the combustion engine; and deriving torque at the output shaft of the engine for powering the drivetrain to propel the vehicle by processing a respective signal correlated to the at least one ambient parameter variable input source and processing a respective signal correlated to the at least one operating parameter variable input source.
The foregoing, along with further aspects, features, and advantages of the invention, will be seen in this disclosure of a presently preferred embodiment of the invention depicting the best mode contemplated at this time for carrying out the invention. This specification includes drawings, now briefly described, followed by detailed description that will make reference to these drawings.